The present invention relates to a method of packing reams of sheets.
More specifically, the present invention relates to a method of packing reams of sheets of paper, to which the following description refers purely by way of example.
A ream of sheets of paper comprises rectangular sheets of paper stacked and aligned to form a rectangular-base prism having two base faces defined by two opposite end sheets in the ream; two opposite lateral faces perpendicular to the base faces, i.e. two faces adjacent to the major sides of the base faces; and two opposite end faces perpendicular to the base faces and lateral faces, i.e. two faces adjacent to the minor sides of the base faces.
Known methods of packing reams of sheets of paper are normally based on the principle of folding a sheet of packing material about a ream to form a tubular package enclosing the ream and having two opposite projecting portions projecting from the end faces; and folding the projecting portions on to the respective end faces.
More specifically, one known method of packing reams of sheets of paper comprises feeding a ream along a given path in a first feed direction parallel to the base faces; arresting the ream of sheets of paper to feed it in a second direction perpendicular to the base faces; placing a sheet of packing material perpendicular to the second direction, i.e. parallel to the base faces; and folding the sheet of packing material into a U about the ream by means of a folding spindle as the ream is fed in the second direction. Once the sheet of packing material is folded into a U, the ream is arrested to form the tubular package by means of movable folding devices.
The above method has the drawback of subjecting the reams without the sheets of packing material to severe acceleration when switching from the first to the second direction. Rapid acceleration in different directions tends to reduce friction between the sheets in the ream and to disarrange the stack, also in view of the fact that the ream is accelerated without the sheet of packing material, which, when partly folded, contributes towards keeping the sheets in the ream aligned. As a result, acceleration of the ream must be kept as low as possible, thus greatly reducing the output of the packing machine implementing the above method.
It is an object of the present invention to provide a method of packing reams of sheets, designed to eliminate the drawbacks of the known state of the art, and which, in particular, provides for obtaining high-output packing machines with no risk of disarranging the sheets in each ream.
According to the present invention, there is provided a method of packing reams of sheets, wherein each ream is defined by sheets stacked to form a rectangular-base prism of a given height, and comprises two base faces defined by respective end sheets in said ream, two lateral faces perpendicular to the base faces, and two end faces; the method comprising feeding said ream along a given path by means of a feed unit, placing a sheet of packing material along the path of the ream by means of a supply unit for supplying sheets of packing material, and conveying the ream and the sheet of packing material through a folding spindle to form a U-shaped fold; the method being characterized by pushing said ream in a feed direction parallel to said base faces, and placing said sheet of packing material crosswise to said feed direction.
The present invention also relates to a machine for packing reams of sheets.
According to the present invention, there is provided a machine for packing reams of sheets, wherein each ream is defined by sheets stacked to form a rectangular-base prism of a given height, and comprises two base faces defined by respective end sheets in said ream, two lateral faces perpendicular to the base faces, and two end faces; the machine comprising a feed unit for feeding said ream along a given path, a supply unit for supplying sheets of packing material and for placing a sheet of packing material along the path of the ream, and a folding spindle located along the path to fold the sheet of packing material into a U about said ream; the machine being characterized in that said feed unit comprises a first conveyor for pushing said ream, at said folding spindle, in a feed direction parallel to said base faces; and said supply unit comprising a conveying device for keeping said sheet of packing material crosswise to the feed direction at said folding spindle.